Recently, a display device which causes a common electrode which is arranged in a display area to function as a display electrode which produces an electric filed between the display electrode and a pixel electrode and also function as a detection electrode which detects an object which is in contact with or in proximity to the display area has been developed.
For example, a liquid crystal display device including a plurality of common electrodes which extend in an extension direction of scanning signal lines (gate lines), are arranged in an extension direction of image signal lines (source lines), and are used as object detection electrodes has been known. In the liquid crystal display device, slits which extend in the extension direction of the scanning signal lines are formed between the common electrodes. Between areas in which the slits are provided and areas in which the slits are not provided, the alignment of liquid crystal molecules may differ. Therefore, it is considered that, as slits are further provided in each of the common electrodes, the impact of the slits can be averaged across the display area.
In realizing common electrodes which function as detection electrodes, if the common electrodes are arranged such that the common electrodes extend in the extension direction of the image signal lines and are arranged in the extension direction of the scanning signal lines, the frame size can be reduced. In this structure, the slit between the adjacent common electrodes extends along the image signal, and thus the electric field from the image signal line may leak through the slit and may have an impact on the display performance. Therefore, even in a display device of this kind, it is still necessary to take some measures to improve display quality.